[daip] Time averaging in SPLAT

[Conrad M. Hirano]

Hello,

I had a few questions about time averaging using SPLAT.  I'm using SPLAT
to extract the data from one of our sources and to apply phase and gain
calibrations.

The documentation for SPLAT indicates that I can set the time interval
over which it averages in minutes using SOLINT.  I wanted to average my
data over one-minute intervals, so I set SOLINT to 1, ran SPLAT, and then
wrote the resulting file to a FITS file using FITTP.

When I examined the headers of the FITS file, I found the following
message:

HISTORY SPLAT  SOLINT =   1.0sec  / => averaged in time

Did it average the data over one-second or one-minute intervals?

I also took a look at the INTTIM parameter for a few groups in the FITS
file.  In the past, I did not average in time, so I used SPLIT (or SPLAT
with SOLINT=0) instead of SPLAT.  The INTTIM parameter had a value of
2.09715 for every group, which I assume is the correlation time in
seconds.  When I use SPLAT, with SOLINT=1, the INTTIM parameter has
varying values, the first few of which were 1.32969e-06, 9.34026e-06,
9.69976e-06, and 9.36529e-06.  Clearly, these numbers are no longer in
units of seconds.

With SOLINT set to 60, things get a bit more confusing.  The first few
values are:

int time = 0.000293572
int time = 0.000127156
int time = 0.000334791
int time = 0.000344174
int time = 1.88985e-05
int time = 1.78486e-05
int time = 1.78486e-05
int time = 1.32969e-06

I am using a copy of the 31DEC99 version of AIPS which I grabbed sometime
during the summer; I haven't been running the Midnight job, however, to
get the latest changes.

Can you tell me what might be going on here?

Thanks.

Conrad Hirano
UC Santa Barbara